#include <stdio.h>

int MyStrlen(char *s)
{
    int count = 0;
    while(*s != '\0')
    {
        count++;
        s++;
    }
    return --count;
}


int main(int argc,char *argv)
{
    char *s = "hello world!";
    printf("len = %d\n",MyStrlen(s));
}